7. Er was Judah’s oldest son. But he did what the Lord said was evil. So the Lord killed him.
8. Then Judah said to Er’s brother Onan, “Go and have physical relations with your dead brother’s wife. It is your duty to provide children for your brother in this way.”
9. But Onan knew that the children would not belong to him. Onan was supposed to have physical relations with Tamar. But he did not complete the physical act. This made it impossible for Tamar to become pregnant. So Er could not have descendants.
10. The Lord was displeased by this wicked thing Onan had done. So the Lord killed Onan also.